The invention relates to a flat ribbon heald with an end eyelet, shaft and thread eye, said heald being manufactured of a metal ribbon section.
Healds are manufactured, for example, of flat steel ribbon during a punching operation. In so doing, parts are removed from a specifically cut metal ribbon in order to obtain the desired exterior form of the heald. The removed parts are waste, which considerably contributes to the consumption of material.
At times, it is necessary to provide healds with a crank, in which case, in particular adjacent healds on a heald shaft are cranked, frequently away from each other in opposite direction. As a result of this, an offset is created between the thread eyes of adjacent healds relative to the longitudinal direction of the warp thread in order to facilitate the passage of warp threads between the healds. Paired healds having shafts with different offsets have been known from documents U.S. Pat. No. 7,204,274 B2, and CH 468 489 and DE 10 2005 033 175 B3. Each of these healds has a straight edge, respectively, extending along the shaft and the end eyelet. The achievable intermediate space between the shafts of adjacent healds is limited.
Furthermore, document U.S. Pat. No. 1,545,904 discloses the manufacture of healds of flat material that forms a relatively narrow sheet metal strip. The end eyelets adjoin the shaft in a symmetrical manner, whereby the shaft may be provided with a crank in order to define an enlarged thread passage space between adjacent healds.
Furthermore, document U.S. Pat. No. 2,973,789 discloses a heald set consisting of differently cranked healds, whereby the healds consist of a metallic flat material. Adjoining the end eyelets, the shafts of the healds are cranked and configured in such a manner that an enlarged thread passage space exists between adjacent healds.
Finally, document U.S. Pat. No. 644,371 discloses a heald that has been manufactured of a narrow steel strip, in which the thread eye and the end eyelet have been produced by spreading apart slotted sections. In addition, the shaft of such a heald may be cranked. During a stamping process, the shaft has been flattened on both sides of the thread eyelet in order to effect increased elasticity in longitudinal direction of the warp thread.
Indeed, the production of elongated openings by slitting and widening is a material-saving process; however, this requires a relatively strong material deformation, thus restricting the choice of material and the possibilities of material optimization.
It is the object of the invention to provide a heald and an economical manufacturing process for the production of said heald, this being intended to make possible a material-saving manufacture of high-performance healds.